Yep - I've known five chemists who syntheized fentanyl homologues and then broke RULE 1.
Two are dead, one is still in jail, the last two were still siffering AWS after 1+ years. The last two spent time in hospital because they weren't eating or drinking and sleep deprivation caused seizure in at least one of them.
Now that is an extreme example. All five ended up IVing their fentanyl homologues every 20 minutes night and day. You may ask how - but as I understand it, they obtained syringe-drivers so a large syringe slowly infusing the drug allowed sleep. An incredibly dangerous thing to do hence the two dead. If even slightly overestimate the volume required, OD would occurs maybe hours later and of course nobody was there to monitor them.
So while methadone isn't in that league, I imagine that a very severe and protracted AWS could result in death due to other causes.
Just last week someone I know ended up in hospital. They had been coughing up blood for three months and their response was to take more H. Then they picked up a back injury and you guessed it, took even more H to deal with the pain. On admission they tested positive for covid as well as two bacterial infections and the result of the TB test are still not known. Now almost any clinician would ASSUME multi-drug resistant TB but the person is so unpredictable, they could never be trusted to complete a course of antibiotics and what you don't want is for someone to make MDRTB to develop resistance to one of the few treatments that still work.
At last count they had managed to run up a £6000+ debt with every single dealer in the city with absolutely no way of ever paying that debt. My wife pointed out that likely the person had decided to self-destruct. They even smuggled H into the hospital in spite of being prescribed a LOT of methadone. Today I learnt that it was 160mg/day. Now NO WAY will our local HR agency provide take-homes. The person would require supervised consumption and they are so chaotic, none of us think they will even get it together enough to go to the pharmacy (10 minutes away).
We sort of conclude that they intend to die.
But on a happier note, I knew someone who was prescribed 200mg methadone/day and while it took them over a year, they stopped and it's now 25 years later and while they may now smoke funny herbs, they aren't using opioids. So if someone REALLY wants to stop, it can be done. I always tell people that if someone cracks one day and buys a bag, fine. But don't think 'I will NEVER be able to stop' - it doesn't matter how many times you fall down as long as you get back up and keep walking,
BTW in the UK at least, when someone gets down to 32mg methadone/day they are offered the option of buprenorphine. We used to use dihydrocodeine which every single former-user I've talked to said was FAR better than buprenorphine. Unlike codine, DHC is active in it's own right so their is only a 'soft ceiling' on the dose, it's duration of action is 6 hours rather than 4 (as for codeine) and at least in the UK, SR formulations are available. I strongly disagree with methadone being used in an attempt to get a client down to zero. At 30mg, A couple of 120mg DHC Continuous every 12 hours works and what is nice is that not only is there 60,90 as well as 120mg DHC continuous, there is also plain DHCs (nicknamed 'Dizzies') which are 30mg pills with a breakline as well as DHC Forte which are 40mg pills with a breakline. I mention this because while the analgesic potency of DHC would suggest it cannot substutue for methadone as an analgesic, in preventing AWS it's only about three-four times less active so 30mg of methadone per day to 60mg DHC QID worked for almost all clients. Now how you obtain DHC I wouldn't know.